This FIRST award application is a proposal to help clarify the validity, reliability, and utility of blood pressure (BP) and lipid screening in childhood. To be useful, a screening program depends on an acceptable, valid, and reliable test, and an efficacious and cost-effective intervention in the population of interest. Screening children to detect those at high risk of adult hypertension of hypercholesterolemia must be examined from this viewpoint. Long-term studies starting in childhood have so far revealed less than optimal validity of BP and serum cholesterol levels in childhood as predictors of adult levels. However, information is sparse regarding reliability of measurements, accounting for which could improve validity. The efficacy of interventions that could be widely applied in childhood has not yet been demonstrated. In addition, the costs of an extensive screening program and risks such as misclassification, side effects, and labeling need to be evaluated. This proposal comprises examination of the following factors that are key elements in the evaluation of screening: 1) within-person variability of BP and lipid measurements (i.e., the reliability of the test) and its impact on tracking of BP and lipids from childhood to adulthood, 2) calculation of predictive values, sensitivity, and specificity of childhood BP and lipid measurements considered as screening tests for adult values, after correcting for within-person variability (i.e., validity), 3) one potentially effective intervention for BP control in children, that is, calcium supplementation, and 4) evaluating the cost-effectiveness of screening to identify children at high risk of developing adult hypertension or hyperlipidemia. The availability of subjects and data from several cohort studies, including the East Boston Blood Pressure Study, the Framingham Offspring Study, and the Framingham Children's Study, makes the proposed studies possible and should allow their completion within the time frame of the FIRST award. In addition, the PI has access to a population of school children to address the calcium-BP relationship. The results of this study should help determine whether screening for risk factors in childhood is a useful method for preventing cardiovascular disease in adults.